diff --git a/scripts/signals.sh b/scripts/signals.sh
index bd48be3..515f7a5 100644
--- a/scripts/signals.sh
+++ b/scripts/signals.sh
@@ -21,5 +21,5 @@ signal_name_to_number() {
 signal_return_val() {
     SIGNAME="$1"
     SIGNUM=$(signal_name_to_number ${SIGNAME})
-    echo "128 + $SIGNUM" | bc
+    echo $((128 + SIGNUM))
 }